Combined scaffold bracket and lock



Feb. 22, 1944. J -r COMBINED SCAFFOLD BRACKET AND LOCK Filed June 27, 1941 Patented Feb. 22, 1944 UNITED STATES PATENT OFFICE 2,342,427 I COMBINED SCAFFOLD BRACKET AND LOCK Henry J. Riblet, Erie, Pa.

Application June 27, 1941, Serial No. 399,987

2 Claims.

This invention relates generally to the platform support and automatic lock which painters and other workmen combine with a suitable upright to form a hoisting scaffold, and it relates more particularl to a combined platform support and automatic lock which is entirely operated by the load on the platform.

In all such platform supports now on the market some extraneous force, provided either by a spring or by a weighted lever, is required for proper operation.

It is, accordingly, an object of my invention to overcome the above and other difficulties in platform supports and at the same time to provide a combined platform support and automatic lock which is economical in manufacture, efficient in use, and economical in cost.

Other objects of my invention will become evident from the following detailed discussion, taken in conjunction with the accompanying drawing, in which:

Fig. 1 is a side view of my novel combined platform support and automatic lock in which part of the upright is shown, as well as the lower portion of ablock and tackle.

Fig. 2 is a top view of the U-shaped member which constitutes the automatic lock.

Fig. 3 is a side view of one of the separators required.

Fig. 4 is a side view of a roller that is used.

The character I denotes an upright which is embraced by the U-shaped band 2 and the automatic lock 3. The automatic lock comprises the U-shaped portion 4, an inner jaw I5, and an outer jaw 5. It is free to rotate about a fulcrum 1 provided by a bolt and nut. The open ends of the U-shaped member 4 are held apart by a separator 8 and at the extreme end of the U-shaped member 4 a hole 9 has been drilled. The open portion of U-shaped member 2 is also held apart by separator 8 upon which freely rolls a roller I 0. The bolt II which secure the two open portions of the U-shaped stirrup 2 also carries an oblique diagonal support I2 and a nearly vertical support I3. Supports I2 and I3 carry a horizontal member I4 to which they are respectively fastened by bolts I5 and I. I6 is a platform carried by the horizontal member I4 and prevented from slipping off of it by the upper end of the oblique support I2. A hole I I has been drilled in the vertical member I3. I8 is a pulley and I9 the rope going through it.

It is clear to anyone familiar with the art that when a load is placed on platform It jaws 5 and I5 will engage the upright I and prevent any downward motion. However, if the operator, by placing his heel on the outwardly projectin jaw 4a of the automatic lock 3, depresses it until the inner jaw 6 has made contact with the vertical support I3, then the platform support may easily be lowered by letting out some rope. Now the operation of the lock depends on th fact that the jaws 5 and 6 and the fulcrum 'I are so disposed that the friction resisting the motion downward increases with the load and always exceeds it. However, some force or agent is required to insure initial contact 0f th jaws 5 and 5 with the upright I. Hitherto, this has been accomplished either manually or by an auxiliary spring or weighted lever. In such devices the danger of mechanical or human failure is always present and so it is the object of this invention to provide a device in which the force which establishes initial contact of the jaws is provided entirely by the load on the platform. This is accomplished by using the outer jaw 5 to resist the turning moment of the platform support about the lower roller I0. It is clear now that as long as there is any load on the platform supporting member a frictional force will exist between the outer jaw 5 and the upright I. During descent the inner jaw 6 will not be in contact with the upright I. It is clear that the resultant force acting on the outer jaw 5 will be upward and outward. Now it is clearly essential that the line joining the fulcrum 1 and the outer jaw 5, when the inner jaw 6 is in contact with the upright I, have a slope which is less than that of the resultant force above mentioned, since otherwise the resultant force on the outer jaw 5 would not be such as to initiate contact between the inner jaw 6 and the upright I. To insure this, it will be observed that in my invention the fulcrum I, the inner jaw 5, and the outer jaw 5 are so disposed relative to each other that when the lock is in its locked position the line joining the fulcrum I and the outer jaw 5 is essentially horizontal. This is accomplished by placing the inner jaw below the plan; determined by the fulcrum I and the outer aw Thus far in the specification I have made the operation of this look depend on the existence of some friction between the outer jaw 5 and the upright I. This, however, is not necessary. It is clear that unlocking the jaws must have some effect on the center of gravity of the platform supporting member. For greatest safety, the center of gravit should be lowest in the locked position. It should be observed that this will be true if the line joining the fulcrum I and the outer jaw 5, in the locked position, is horizontal or downward to the right. Thi is accomplished by placing the inner jaw 6 sufficiently below the plane determined by the fulcrum I and the outer jaw 5.

It will be evident from the foregoing description that I have provided a combined platform supporting member and automatic lock which depends for its operation only upon the existence of some load on the platform, which is at the same time exceedingly simple in construction and economical in manufacture, and which is very efficient in use.

Various changes may be made in the specific embodiment of the present invention without departing from the spirit thereof, or from the scope of the appended claims.

What I claim is:

1. A scaffold locking device in combination with a platform supporting frame and an upright, means slidably connecting the lower portion of said frame to said upright, a lock and lock pivoting means that pivotally fastens said look at one end portion to said frame, said lock embodying an outer jaw a'ndan inner jaw which are so positioned relative to each other and said look pivoting means that in looking position-said outer jaw and lock pivoting means are in substantially horizontal alinement and said outer-jaw and inner jaw bear against said upright and said inner jaw is lower than'said lock pivoting means, and in unlocked position said outer jaw bears against said upright and said inner jaw is spaced inwardly away from said upright and is farther below said lock pivoting means than when said look was in looking position.

2. A scaffold locking device in combination with a platform supporting frame and an upright, said frame embodying an upwardly extending member, a laterally extending member and a diagonally extending member connected to and ex tending between said other two members, means slidably connecting the lower portions of said upwardly and diagonally extending frame members to said upright, a, lock and lock pivoting means that pivotally fasten said look at one end portion to an end portion of said laterally extending frame member, said lock embodying an outer jaw and an inner jaw which are so positioned relative to each other and said lock pivoting means that in looking position said outer jaw and inner jaw bear against said upright and said inner jaw is lower than'said lock pivoting means and in unlocked position said outer jaw bears against said upright and said inner jaw is spaced inwardly away from said upright and is farther below said lock pivoting means than when said look was in locking position, a pin member connecting the lower portions of said upwardly and diagonally extending frame members to said first means, said pin member being located laterally intermediate of said lock pivoting means and said inner jaw.

HENRY J. RIBLET. 

